Stresses good technique while allowing the Athlete to sit back onto a box, keeping their shins vertical, placing the load onto the hips. Allowing for quicker recovery. Adding accommodating resistance, bands, loads the top end of the lift forcing the Athlete to bring their hips to the bar quickly. In a nut shell, squatting onto a box works on starting strength. Adding a band focuses on the lock out of the hips.
How?

See video below